[NONTUBERCULOUS MYCOBACTERIAL PULMONARY DISEASE].

The prevalence of nontuberculous mycobacterial (NTM) pulmonary disease is increasing in Japan and worldwide, and the importance of proper diagnosis and management of the disease has been recently recognized. Mycobacterium aviun complex (MAC) is the most common and important causative agent of pulmonary disease among nontuberculous mycobacteria. I have described the latest epidemiology of NTM lung disease, clinical feature, disease type, disease progression, diagnosis including serodiagnosis, and treatment strategy of MAC lung disease in this report. There are a lot of unsolved problems in the field of NTM lung disease, therefore, further investigations are required.